Question

A biconvex lens of focal length $f_{1}=10\,cm$ is placed $40\,cm$ in front of a concave mirror of focal length $f_{2}=7.50\,cm,$ as shown in the figure. An object, $2\,cm$ high, is placed $20\,cm$ to the left of the lens.

The image formed by the lens, as rays travel to the right, is

• A. Real and erect
• B. Virtual and erect
• C. Real and inverted
• D. Virtual and inverted

Answer 1

Answer: (C)

From lens equation,
$\frac{1}{v}-\frac{1}{\left(- 20\right)}=\frac{1}{10} \, \, \Rightarrow \, \, \, v=+20cm$
Magnification, $m_{1}=\frac{v}{u}= \, \, \left(\frac{+ 20}{- 20} \, \right)=-1$
Image is real, inverted, and same size as object.